Which ones can I risk putting out?

Kmeh

I totally started too early on the seed sowing and my greenhouse is not coming till early/mid may (I hope!). Got a little over excited!

I would like to move some outside but from my reading I pretty much can't move any till risk of frost is over and lord knows when then could be in Yorkshire! 

Any advice on which ones I can be a little brave and slowly harden off outside:

Flowers

Anthirithums
Scabiosa (think these might be ok?)
Cleome
Sweet Peas (think these are ok?)
Cosmos
Dahlias

Veg

Tomatoes
Cucumbers 
French beans
Chillies
Celery

I also bought a few tiny camelia plant that I've kept inside and they've have quadrupled their leaves in a matter of weeks. It's done so well, I'm nervous to put it too.

Any advice very appreciated!

Thank you 

RubyLeaf

I don't suppose you have any fleece at hand? Maybe some bubble wrap?

I wish I could help better, but I don't want to give out guesses

pansyface

My mother, who gardened in Sheffield for fifty years, always waited until the first of June to be sure not to catch a late frost.

 She hardened them off by putting them outside on sunny days but always brought them in at sundown, just to be sure.

Obelixx

Sweet peas will be OK in a sheltered corner if they've been hardened off but all the rest need protection from frost and the veg won't be happy below 10C.

Astro

The best bet is to check the hardiness rating. I've had celery out over winter. The other veg to the best of my knowledge from growing is more suited to going out after risk of frost. Anthirithums, scabiosa and sweet peas I have had over wintered.

As suggested you could always use cover if frost is predicted and put them closer to the house or under shelter too. 

Kmeh

What type of fleece is it? Some type of horticultural fleece? Apologies for ignorance!

purplerallim

You don't happen to have a plastic greenhouse do you. Some could go in there mid April. If not it's too cold yet for most things.

GemmaJF

You can check your local last frost date here:

https://www.gardenfocused.co.uk/adjust-dates-uk.php

I put stuff out during the day and bring it all in at night at this time of year. Potting shed, garage, anywhere I can put it. 

Liriodendron

Yes, horticultural fleece.  You can use more than one layer if it's going to be very cold...  

celcius_kkw

I live in an apartment so have no access to greenhouses.. I also sowed mine (sweet peas) too early and they had already filled up the root trainers.. I took the risk and planted half out in a large pot on my rather exposed terrace and the other half in 2 litre pots which I’ve kept on my sunny windowsill for now. I live in the north west and I think the last frost is predicted to be some time this month? 

Obelixx

Sweet peas are hardy.  Some people sow them in autumn and leave them in cold frames to get ahead for an early start in spring.

If you can pot seedlings and small plants on to the next size of pot their roots will have better protection and you can cover them at night with cardboard if you don't have fleece.  Just make sure it's not resting on the small plants and that you take it off in daylight, after any frost has thawed.   

Mid May used to be the last frost in the north west but maybe global warning has advanced that date.  You'll have to keep an eye on forecasts and be aware that the coldest hour is around dawn.